I've created a spreadsheet and formatted my cells. All is working fine. I
open another worksheet and copy column A and paste it into my working
spreadhsheet and all the fomulas revert to their text language and don't show
the answer. I don't know what happened and I can't reformat the cell. It's
like everything is frozen.

example: Cell F8 now shows =SUM(F2:F7) and not the sum.
Is there a solution or is there possibly a error in the program?